title: A polymer model explains the complexity of large-scale chromatin folding.
abstract: The underlying global organization of chromatin within the cell nucleus has been the focus of intense recent research. Hi-C methods have allowed for the detection of genome-wide chromatin interactions, revealing a complex large-scale organization where chromosomes tend to partition into megabase-sized "topological domains" of local chromatin interactions and intra-chromosomal contacts extends over much longer scales, in a cell-type and chromosome specific manner. Until recently, the distinct chromatin folding properties observed experimentally have been difficult to explain in a single conceptual framework. We reported that a simple polymer-physics model of chromatin, the strings and binders switch (SBS) model, succeeds in describing the full range of chromatin configurations observed in vivo. The SBS model simulates the interactions between randomly diffusing binding molecules and binding sites on a polymer chain. It explains how polymer architectural patterns can be established, how different stable conformations can be produced and how conformational changes can be reliably regulated by simple strategies, such as protein upregulation or epigenetic modifications, via fundamental thermodynamics mechanisms.
authors.affiliation: Universita' di Napoli "Federico II"; Dipartimento di Fisica; INFN Sezione di Napoli; CNR-SPIN, Complesso Universitario di Monte S. Angelo; Napoli, Italy; Department of Biochemistry and Goodman Cancer Research Center; McGill University; Montréal, Québec Canada; Berlin Institute for Medical Systems Biology; Max Delbrück Center for Molecular Medicine; Berlin-Buch, Germany; Genome Function Group; MRC Clinical Sciences Centre; Imperial College London; Hammersmith Hospital Campus; London, UK.
authors.forename: Mariano
authors.initials: M
authors.lastname: Barbieri
authors.forename: James
authors.initials: J
authors.lastname: Fraser
authors.forename: Liron-Mark
authors.initials: LM
authors.lastname: Lavitas
authors.forename: Mita
authors.initials: M
authors.lastname: Chotalia
authors.forename: Josée
authors.initials: J
authors.lastname: Dostie
authors.forename: Ana
authors.initials: A
authors.lastname: Pombo
authors.forename: Mario
authors.initials: M
authors.lastname: Nicodemi
mesh_terms: D002467:Cell Nucleus; D002843:Chromatin / Q000737:chemistry* / Q000378:metabolism*; D006801:Humans; D008958:Models, Molecular; D011108:Polymers / Q000737:chemistry* / Q000378:metabolism
chemical_list: D002843:Chromatin; D011108:Polymers
keywords: FISH; Hi-C; chromatin organization; polymer physics; statistical mechanics